Clutch operating mechanism



Jan. 22, 1952 H. N. STEPHAN 2,583,065

CLUTCH OPERATING MECHANISM Filed Feb. 25, 1948 s Sheets-Sheet 1 INVENTOR Haul: h. 575F499 wawz zzq mm ATTORNEYS Jan. 22, 1952 H. N. STEPHAN 2,583,065

CLUTCH OPERATING MECHANISM Filed Feb. 25, 1948 5 Sheets-Sheet 3 III . INVENTOR. Ki BY flan/s A! 5752/14 Patented Jan. 22, 1952 signor, by mesne assignments,

to The. New

Britain Machine Company,.New Britain, Conn, a corporation of Connecticut application Febrfiary 25, 1948; Serial No. 10,615

6' (llaims. (01574 -365) I The present invention relates to electrically ac+ tuated or controlled means for shifting or moving machine parts, such as the movable element or elements of a clutch, either friction or jaw, or the movable element or elementsof a: sliding gear speed change transmission and to machine tools, especially horizontal boring,.drilling and milling machines embodyingsuchmechanism.

The principal objectof therinventionis' the provision of novel and improved, electrically actuated or controlled mechanism for moving. or shifting a movable member, such as the'niovable element or elements of a clutch, the. movableelement or elements of a sliding gear speed change transmission, etc., which mechanism will bereliable and comparatively silentin operation and which will not subject the various parts to undue shock and strain, etc., and will otherwise be more satisfactory than devices heretofore employed for like purposes.

Another object of the invention is the prc'vh sion of a novel and'improved, electrically actuated or controlled mechanism including a solenoid for moving or shifting a movable member, such as the movable element or elements of a clutch, the movable element or elements of aslid; ing gear speed change transmission,-etc., wherein the mechanical connection -between.the-solenoid and the member moved thereby includes at tension spring, which spring collapses to formarigid column when the solenoid is deenergi'zed:

Another object of the invention is the provision of a novel machine tool, such as a hori-'- zontal boring machine, comprising apower'transmission device including a disengageable drive connection, such as aclutch, either frictionor positive drive, or a sliding gear speed: change transmission, and an electric solenoid meansfor moving the movable element or elements to em gage or disengage the drive, etc.,and wherein the tails of constructionand combinations and'a'rrangements of parts, and further objects and advantages thereof will be apparent to those skilled in the art to which the inventionrel'at'es; from the following description of the preferred'em bodiment thereof described with reference to the.

accompanying drawings forming apart of this specification, in which similar reference characters. designate corresponding parts, and in which Fig. 1 is a perspective view of a horizontal boring, milling and drilling machine embodying the present invention;

Fig. 2 is a diagrammatic view of the spindle head, table, and saddle feed and rapid traverse transmission of the horizontal boringmachine shown in Fig. l; v

Fig. 3 is an enlarged, fragmentary, sectional view, with portions in elevation, approximately on the line 33 of Fig. 2; V

Fig. 4 is a front elevational view of the pendant control station;

Fig. 5 is a diagrammatic view of the spindle speed change transmission of the horizontal boring machine shown in Fig. l; and

Fig. 6 is an elevational view of the righthand side of the pendant control station shown-in Figs. 1' and 4.

While the present invention is susceptible of general application, it is particularly applicable to electrically controlled machine tools, such as the pendant controlled horizontal boring machine shown in United States patent to Lucas, et a1.,-No. 2,208,312,. issued July 16, 1940, and is herein shown and described as embodied in such a machine. Only those parts of the machine which are necessary to a complete understanding of the present invention are herein shown and described. Reference is made to the aforesaid patent" for a complete disclosure of the other parts of the machine. erence. characters are used to facilitate ref.- ence to the patent.

Referring to the drawings, the machine shown therein comprises a base A provided at one end with a spindle head column 13 having vertical-ways It and ll on the front face thereof, upon which Ways a spindle head C is mounted forvertical movement. At the other end of the base or bed A, a backrest or outboard support column D is provided. This backrest or outboard support column is sli'dably supported on horizontal ways l2 and I3 formed on the upper side of the bed. The ways 12 and l3 also have slidably supported therein a saddle E, the upper side of whi'chis provided with horizontal ways which in turn support a work table F. A backrest block G is slidably supported for movement along vertical ways formed on the backrest column. The spindle head C which is counterbalanced by a-weight (not shown) is adapted to be moved vertically along the ways l0 and H by Where possible, the same ref-.

a lead screw I8 rotatably supported in the base A and the spindle head column B and having threaded engagement with a nut fixed in the spindle head. The spindle, designated generally by the reference character IS, in addition to being rotatable in opposite directions, is movable in opposite directions longitudinally of its axis to effect both feeding and rapid traversing movements.

The speed and direction of rotation of the spindle, etc., and the different movements of the various elements, such as the feed and rapid traverse of the spindle, head, saddle, table, etc., are performed by power and their operation may be controlled from any convenient place about the machine. In the embodiment of the invention shown, five electric motors are employed to perform the various movements or operations as follows: a reversible motor 2 i, commonly referred to as the feed and rapid traverse motor, supported on the bed within a guard 22 adjacent to the left-hand end of the machine; a reversible main driving motor 23 arranged for ceiling mounting, also enclosed within the guard 22; a spindle rapid traverse, reversible motor (not shown) mounted on the head C; a reversible motor 24 for clamping and releasing the backrest block; and a reversible motor (not shown) for moving the backrest column D.

The feed and rapid traverse motor 2! is connected to the saddle and table feeding and rapid traversing mechanism and to the spindle head and backrest raising and lowering mechanism. The motor 23 is connected to the spindle rotating and feeding mechanism, and the spindle rapid traverse motor actuates the rapid traverse for the tool spindle. The motors are adapted to be selectively connected to the various operating elements through the medium of suitable speed change transmissions, shafts, gears, clutches, etc., the controls for which are located on or adjacent to the base A, spindle head C, and/or pendant control station H fixed to the lower end of a pipe 25 connected to a universally movable arm 26 by flexible cable 21. v

The shaft 34 to which the spindle head, saddle,

and table operating mechanisms are adapted to be selectively connected in the manner disclosed in the aforesaid patent is adapted to be driven in either direction depending upon the direction of rotation of the motor 21 at different comparatively low feed rates through a speed change transmission J or at a high rapid traverse rate. The electric motor 2i is operatively connected to the transmission J by a V-belt drive and spur gears 35 and 37. The gear 31 is selectively connected to the shaft 34 to rotate the same at a relatively high rate of speed through a gear 45 and the normally disengaged, left-hand side of a double friction clutch V. The speed change transmissionJ is selectively connected to the shaft 34 through the gears 44, 45 and the normally engaged, right-hand side of the friction clutch V. Reference to the aforesaid patent will show that the mechanism employed therein for connecting the gears 31, 44 to the shaft 35 is herein replaced by the gears 45, 45 and the double friction clutch V.

The clutch V shown is of commercial construction and is a Maxitorq floating disk, self-locking, double clutch sold by The Carlyle Johnson Machine Company, 52 Main Street, Manchester, Connecticut, and is shown in Sweet's File for Product Designers, 1944, to which reference is made for a more complete disclosure thereof, if necessary. The clutch comprises left and righthand driving cups or hubs 45, 4! rotatably supported by means of bushings 5B, 5! on the shaft 34 and to which driving cups the gears 45 and 45 are keyed. The driving cups 43, 4'5 are operatively connected to the left and right-hand series of driving disks, respectively. The left and righthand series of driven disks are keyed to a sleeve 52 extending between the bushings 5t, 5i and keyed to the shaft 34. The construction is such that when the left-hand side of the clutch is engaged, thesleeve 52 and, in turn, the shaft 34 is driven from the gear through the driving cup 46 and when the right-hand side of the clutch is engaged, the sleeve 52 and, in turn, the shaft 3-2 are driven from the gear through the driving cup 41.

Opposite sides of the double clutch V are adapted to be selectively engaged by the shifting of a sleeve member 53 slidably supported on the clutch body 54 and provided with two series of inwardly extending lugs 55 projecting into suitable slots in the body member 54 and each provided with an inclined cam surface 55. Each of the two series of lugs are spaced axially with respect to each other and face in opposite directions. The construction is such that as the sleeve member 53 is shifted to the right or to the left from its normal intermediate position with both sides of the clutch disengaged, the cam surfaces 56 on one series of lugs 55 engage one set of levers or members 51 and move the same to engage one side or the other of the clutch depending upon which direction the sleeve 53 is moved. After the sleeve member 53 has been moved a sufficient distance to engage one side or the other of the clutch, continued movement thereof causes the radial inner ends of the lugs 55 to engage over the free ends of the members 5! and hold the clutch engaged even though the force applied to the sleeve 53 in shifting it from its neutral intermediate position to its engaged position is removed. The clutch is, therefore, said to be selflocking or holding.

In the embodiment of the invention shown, the sleeve 53 of the clutch V is adapted to be shifted from its disengaged position to one or the other of its engaged positions and returned to disengaged position by a member 60 pivotally con nected as by a pivot pin 5! to a suitable part of the frame of the machine or the gear box within which the speed change transmission J and the clutch V are housed. The member 60 includes a yoke member 62, the arms of which project to opposite sides of the sleeve member 53 and carry rollers that engage within a groove 63 in the sleeve member 53. In addition to the yoke member just referred to, the member 65 includes oppositely extending arms 64, 65 projecting at right angles to the yoke member 62.

The projecting ends of the arms 64, 65 are connected to armatures 66, 61 of electromagnetic solenoids 68, 69, respectively, by composite links comprising springs 10, H, the upper ends of which are connected to yoke members 12, 13, respectively, the upwardly projecting, double arms of which yoke member are pivotally connected to the arms 64, 65 by pins 14, 15. The members "I2, 13 include downwardly extending, threaded bosses 15, TI, respectively, and the upper ends of the springs are secured thereto by merely being threaded or screwed onto the bosses. The lower ends of the springs 10, H are pivotally connected to the armatures 6B, 61 of the solenoids by yoke members 11, 18 similar to the yoke members 12,

5 are of such: a length and constructlon that when one of the solenoids, tor example, thesolenoid 69 is energized to shift the sleeve member 53 to engage the right-hand side of-the clutch V, the

spring elongates slightly allowing the armature .1.

sleeve member 53 toward its neutral position. As

soon as the sleeve 53 has been moved. a. sufilcient distance to allow the free ends of thejulv vers 52 to engage the cam surfaces 55, the natural tendency for the clutch to disengage continues or assists in continuing the movement-of the sleeve 53 to neutral position. In the particular embodiment of the invention shown, the movement of the sleeve 53 to disengaged position is assisted, if necessary, by the opposite solenoid.

The energization of the solenoids 68,, 65, as

shown, is controlled by a push button switch so having normally closed and normally open contacts. The push button switch 80 replaces the rapid traverse push button switch 461 of the aforesaid patent andis located in the same posi- ,1;

tion on the pendant control station H, which pendant control station also includes numerous other switches for controlling other operations of the machine, all of which, with the exception of two switches hereinafter specifically referred to, 2.;

are the same as those shown andd'escribed in the aforesaid patent. The normally closedcontacts of the switch 80 are inseries circuit across the supply lines 82, 83 with the operating coilof a relay 8! provided with both normally open and normally closed contacts. The normally open contacts of the relay 8i, which contacts are shown closed because the operating coil is energized, are in series circuit across the supply lines 82, 83 with the solenoid 6'9. As soon as the main power or line switch for the machine is closed, therelay 8| operates to close its normally open contacts and energize the solenoid e9 to engage the right-hand or feed side or the clutch V so that the feed is always connected except when the push button switch at is depressed to engage the left-hand or rapid traverse side of the clutch.

The normally open contacts of the switch at are in series circuit across the supply lines 82', 83

with the operatin solenoid of a second relay 84.

The normally closed contacts of relay 81, which contacts are shown open, are in series circuit across the supply lines 82,. 83 with a normally open limit switch 35' now closed by thearm 65 since the solenoid 69 is energized, and the solenoid 68 the. armature of which is connected to the arm as. The normally open contacts of the relay 8% are connected in series circuit across the lines 32, 83 with the solenoid 58 in a manner similar to that in which the normally open contacts of relay 8| are connected in series circuit with the solenoid 69, and the normally closed contacts of relay B l are connected in series circuit across the lines 82, 83 with the normally open limit switch 86 corresponding with the switch 85, and

the solenoid Ed. The limit switch 86 is adapted to be closed by the arm 64 when themember as is in position to engage the left-hand or rapid traverse side of the clutch V. The construction is such that upon deenergi'zation ofthe operating coil of either or the rela s: l1, scans, intern-,- the solenoid 68' or 69 associated therewith, the other solenoid, either 68 or 69 as-the case-may be; is.

, perform a given operation thanwould otherwise be the case and that the noise is reduced because the armatures of the solenoidsmay bottomor abut against a fixed member such; as the coils of the solenoids, thereby-reducing vibration, etc. It will also be apparent that the solenoids neednot be perfectly aligned-with the parts connected to their armature's for best operation because slight variations in alingmentwill be taken care of by thesprings. Smaller and less powerful solenoids may be employed becausethereverse movement of the members shifted by the solenoids is eifected or assisted by the hammerblow effect produced by the sudden release of the relatively heavy armature of the solenoid and-- the energy stored in the spring which connects: the-armature with the member, thus eliminating the necessity of having heavy or powerful springs to perform-this function, the force of which springs must be overcome in moving themember to engaged or operative position. It will be apparent-that inorder to get the desired action from the springs 10, H, the solenoids must be so constructed and located that they will stretchthe springs an appreciable amount after the side of the clutch with which they are associated is engaged. The length of the links formed lay-the tension springs and their associated yoke members can be readily adjusted by screwing the spring further on or ofi one or both ends of the threaded studs to which the spring is connected. If desired, a jam nut/can be placed between the end of the spring. and the yoke member but this is ordinarily not required.

As load is applied to the spring it tends to contract radially and more tightly grip the studs to which it is connected.

While a double acting, friction clutch of the seli-locking type has been illustrated, it is to be understood that the invention is equally applicable to law type clutches and clutches which are not of the self-holding or looking type. The particular clutch shown can be readily converted to one of the non-self holding or looking type by limitingthe axial movement of thesleeve E3 to an amount less than that required to cause a the lugs 55 to overlie the free ends of the'levers If desired, a light spring may be employed to center the shiftabie clutch member and hold the clutchdisengaged. This maybe particularly desirable in the case of ajaw clutch so as to avoid any possibility of the jaws accidentally meshing due to vibration, etc. It is also to be understood that oscillating electromagnetic motors may be substituted for the reciprocating motors exemplified by the'solenoids shown.

Figs. 5 and 6 show the invention applied to the shii'tingoi a gear cluster inthe speed change transmission of the spindle drive of the machine shown in Fig. 1. Thespindle l5 oithemachine is adapted to be rotated ativarious ratesof speed 'bythe'motor 23 through the medium of a speed change transmission, designated generally by the reference character P, which transmission is housed in a suitable gear box 209 supported in the bed of the machine. The transmission P is connected-to the spindle I9 by mechanism shown in the aforesaid patent, including the vertical shaft 2I0, the lower end of which is rotatably supported in the gear box and is connected to the output shaft 2I'I of the transmission P by miter gears 2I8, 2I9.

The driven shaft 2H of the transmission P is operatively connected to the motor 23 through the medium of a V-belt drive 2I'2 and gears 2I3, 2M, the latter of which is fixed to the shaft 2| I. The shaft 2H carries a three-gear cluster 220 slidably splined thereto, the three gears of which, designated 90, and 92, are adapted to selectively engage gears 93, 94 and 95, respectively. The gear 93 is one of a two-gear cluster 223 fixed to a shaft 224 rotatably supported in the speed change gear box in the base of the machine, as are the other shafts of the gear box, and the gears 96, 95 are part of the three-gear cluster 222 also fixed to the shaft 229. The splined shaft 2 I1 carries a three-gear cluster 22I slidably splined thereon, the gears 96, 91, 98 of which are adapted to selectively mesh with gears I00, 93, IOI, respectively. The gear I00 forms a part of the two-gear cluster 223, and the gear IOI forms a part of the three-gear cluster 222 both of which gear clusters have been previously referred to.

Different speeds can be obtained by moving or shifting the gear clusters 220 and 221 to different positions. According to the provisions of the present invention, the various positions of the gear clusters 220 and 22I are controlled by electric means from a remote point. As shown, the position of the gear clusters is controlled by electric switches I05, I06 located on the right-hand side of the pendant control station H which includes numerous other switches for controlling other operations of the machine. The mechanisms for shifting and/or controlling the positioning of the gear clusters 220 and 22I are identical and only the mechanism employed for shifting and/or controllin the positioning of gear cluster 22E is shown in the drawings and will be herein described.

The yoke member 226 through the medium of which the gear cluster 22I is moved or maintained in any position, is carried by a rod I01 slidably supported in the speed change gear box 209. The rod I01 and the yoke member 226 are continuously urged to a position where the gears 93, 91 of the clusters 223 and 22I, respectively, are in mesh, which position will be hereinafter referred to as the intermediate position, by compression springs H0, III surroundingthe rod I01 and engaging opposite sides of the yoke member 226 and the sides of the gear box 209. Alternatively the intermediate position may be a neutral disengaged position, and/or other suitable abutments may be provided for the springs H0, III. The rod I01 is adapted to be shifted or moved toward the right, as viewed in Fig. 5, to

disengage the gears 93, 91 and engage the gears 98, f by an electromagnetic solenoid I I2 which, when energized, pulls the rod I01 toward the right. In like manner, the rod I01 is pulled toward the left to disengage the gears 93, 91 and engage the gears 96, I00 by a similar solenoid H3. In the embodiment shown, the solenoids H2, I I3 are in axial alignment with the rod I01 and are connected thereto by springs H4, H5 similar the springs10, 1I previously referred to. The

inner ends of the springs H4, H5 are connected to opposite ends of the rod I01 by being directly screwed upon the ends of the rod which are threaded. The opposite ends of the springs are pivotally connected to the armatures H6, H1 of the solenoids H2, H3 by yoke members H8, H9, respectively, similar to either of the yoke members 11, 10 previously referred to.

The solenoids I I2, I I3 are adapted to be selectively energized by the three position switch I05 located at the top of the right-hand side of the pendant control station H, see Fig. 6. When the switch I05 is in its intermediate position marked "2 in the drawings, that is, the position shown in the drawings, neither of the solenoids I I2, H3 are energized, but when the switch I05 is turned to its right-hand position, that is. the position marked 3" in the drawings, a circuit is completed from the line I20 through the operating coil of relay I2I having both normally open and closed contacts, to the line I22. Energization of the operating coil of relay I26 closes the normally open contacts thereof, completing a circuit from the line I20 through the solenoid H2 to the line I22.

Energization of the relay I I2 causes the armature Ht thereof to pull the rod I01 to the right disengaging the gears 93, 91 and engaging the gears 98, MI. Movement of the rod I01 toward the right is limited or stopped when the gears 98, IOI become fully engaged by the spring III which becomes fully compressed when the gears 98, IM are properly meshed. The spring H4 elongates and the armature H6 continues to move, however, until the armature bottoms in the coil of the solenoid I I2 or abuts against some other suitable fixed stop. When the solenoid I I2 is deenergized by movement of the switch I05 to one of its other positions, the spring H4 quickly pulls the relatively heavy armature H6 toward the rod I01 and when the spring collapses, the armature strikes the end of the rod a hammer blow through the spring which then forms a solid link or column. The hammer blow effect produced on the end of the rod I01 releases the gears if they tend to stick in mesh because of some load remaining thereon, etc., and shifts or assists in shifting the gears into another position. Another advantage of using springs of the character contemplated to shift gears, jaw type clutches, etc., resides in the fact that if the teeth are aligned and will not go in mesh, the spring will merely elongate keeping tension on the member and when relative rotation takes place between the toothed members, as upon the starting of the motor associated therewith, the teeth will pull into mesh.

When the switch I05 is turned to its left-hand position, that is, to the position marked "1 in the drawings, the solenoid H3 will be energized through a relay I23 in a manner similar to that in which the solenoid I I2 is energized when the switch I05 is in its right-hand or No. 3 position. Energization of the relay I I3 causes its armature H1 to pull the rod I01 to the left through the spring I I5 to engage the gears 96, I00. Movement of the rod I01 to the left past a position where the gears 96, I00 are properly meshed is limited or prevented by the spring H0 which collapses to form a positive stop when the gears are meshed.

Continued movement of the armature H1 to the left after further movement of the rod I01 is impossible elongates the spring H5. The solenoid H3, like the other solenoids, is preferably so constructed that the armature H1 will bottom 5 in the coil of the solenoid or abut some other suitable fixed stop. .As previously stated, the sole,- noids must be so constructed and located that when their armature's reach the lirnit of their travel upon energization oflthe solenoids, the springs associated therewith must be stretched an appreciable amount to obtain the desired spring action or hammer effect upon deenergi'zation of the solenoids.

Like the embodiment of the invention shown in Fig. 2, the present embodiment utilizes the deenergize'd solenoid to assist, if necessary; in the disengagement of the engaged gears andthe return of the gear cluster to its intermediate position upon deeneigization of one or the other of the solenoids I I2, I B. This is accomplished by the use of normally open limit switches 12 i, 125 adapted to be closed bya projection on the yoke member 226 when the rod H3] is shifted to .the right or left, respectively. The switch 124 is in series circuit across the supply linesIlZil, 1.22 with the normally c'losedcontacts of relay EM and solenoid H3. Thearrangeinent is such that upon the deenerg'ization of the operating coil of relay i2! and in turn the solenoid H2, the normally closed contacts of relay 12! close establishing a circuit through solenoid H3 until the yoke member 2.25 has movedto the left a sufiicient distance to allow the switch 12 to open, which distance is preferably that required to disengage thelgears 98,, ill]. The switch i235 4 is connected in series circuit with the normally. closed contacts of relay 123 and solenoid H2 and operates to energize solenoid 6122 until the gears 95, Hill are disengaged upon dee'nergization of the solenoid H3, The springs us, m

are comparatively light and do not materially interfere with the action of the solenoids I I2, 53, etc., and are preferably only of su-fiicient strength to return the gear cluster to its normally intermediate position shown in the drawings when neither the gears 86, Ill!) or the gears 98, NH are engaged; however, the springs may he of greater strength, if desired. I I

From the foregoing description of the preferred embodiments of the invention, it will be apparent that the objects heretofore enumerated. and others have been accomplished and that a novel and improved mechanism including solenoids has been provided for moving a member such as the movable element of a clutch or speed change transmission and that there has been provided a novel and improved machine tool, particularly a horizontal boring machine comprising remote control mechanism including a solenoid for shifting various machine elements-thereof, such as change gears, clutches and the like. preferred embodiments of the invention have been described with considerable detail, I do not wish to be limited to the particular construction shown which may be varied within the scope of While the this invention. It is my intention to cover hereby all adaptations, modifications and uses thereof which come within the practice of those skilled in the art to which the present invention relates.

Having thus described my invention, I claim:

1. In a machine tool or the like having a selec tive drive mechanism including an operating member shiftable to and from a predetermined position, mechanism to shift said member comprisin in combination, electromagnetic means including an element movable to one position in response ts energization of said means, and a normally collapsed tubular coil spring interconnecting said member and element, the length of said spring and the travel of said element being such that when said meniber is in said predetermined position and saidlnieans is deenergized said spring is collapsed with the convolutions engaging one another and forming a substantially non-compressible thrust member between said element and member and when said means is energized said spring is stretched to urge said member .to said predetermined position, whereby upon deenergization of said means said spring collapses and draws said element thereagainst and transmits the kinetic energy of said element therethroug'h to "said member to tend to shift saidmernber from said predetermined position.

2. In a machine tool or the like having a selective drive mechanism including an operating member shiftable to and from a predetermined position and tending to remain in said position, mechanism to shift said member comprising in combination, a solenoid, an armature associated with said solenoid and movable'to one position in response to energization of said solenoid, and a normally collapsed tubular coil spring interconnecting said member and armature, the length of said spring and the travel of said armature being such that whensaid member is in said position and said solenoid is dee'nergiz'ed said spring is collapsed with the convolutions engag ing one another and forming a "substantially noncompressible thrust member between said arma- ,ure and member and when said solenoid is energized said spring stretched to urge said member to said predetermined position, whereby upon deenergization of said solenoid said sprin collapses and draws said armature thereagainst and transmits the kinetic energy of said armature to said member to-tendjto shift said member from said predetermined position.

3. In a machine tool or the like having a selective drive mechanism including an operating member shiitable between two predetermined positions, mechanism for shifting said operating member from one position to the other comprising a pair of electromagnetic means each including an element movable to one position in response to energi'za'tion of the respective means,

and a pair of means interconnecting said op-- erating member and said elements respectively, one of said pair of means being resiliently flexed when the element connected therewith is moved to its one position to urge said operating member to one of said predetermined positions and when said one electromagnetic means is deenergized said one of said pair of said means snap moves the last mentioned element thereagainst and forms a substantially non-compressible thrust column which transmits the kinetic energy of said last mentioned element therethrough to said member to tend to move said member from said one predetermined position, and when the other of said electromagnetic means is energized the element: associated therewith is moved to its one position and resiliently flexes the other of said pair of means to resiliently urge said operating member to the other of said predetermined positions and when said other electromagnetic means is deenergized said other of said pair of means snap moves the last mentioned element thereagainst and forms a substantially non-compres sible thrust column which transmits the kinetic energy of the last mentioned element therethrough to said member to tend to move said member from said other predetermined position.

In a machine tool or the like having a selective drive mechanism including an operating a i 11 member shiftable between two predetermined positions, mechanism for shifting said operating member from one position to the other comprising a pair of electromagnetic means each including an element movable to one position in response to energization of the respective means, and a pair of normally collapsed tubular coil springs acting as substantially non-compressible thrust members when collapsed interconnecting said operating member and said elements respectively, the length of said springs and the travel of said elements being such that when one of said means is energized the element thereof is moved to its one position and stretches the spring connected therewith to urge said operating member to one of said predetermined positions and when said one means is deenergized said spring collapses and snap moves the last mentioned element thereagainst and transmits the kinetic energy of said last mentioned element therethrough to said member to tend to move said member from said one predetermined position, and when the other. of said means is energized the element associated therewith is moved to its one position and stretches the spring attached thereto to resiliently urge said operating member to the other of said predetermined positions and when said other means is deenergized the last mentioned spring collapses and snap moves the last mentioned element thereagainst and transmits the kinetic energy of the last mentioned element therethrough to said member to tend to move said member from said other predetermined position.

5. In a machine tool or the like having a selective drive mechanism including an operating member shiftable between two predetermined positions and tending to remain in said positions, mechanism for shifting said operating member from one position to the other comprising a pair of solenoids, an armature associated with each of the respective solenoids and movable to one position in response to energization of the respective solenoids, and a pair of normally collapsed tubular coil springs acting as substantially non-compressible thrust members when collapsed interconnecting said operating member and said armatures respectively, the length of said springs and the travel of said armatures being such that when one of said solenoids is energized the armature associated therewith is moved to its one position and stretches the spring connected therewith to urge said operating member to one of said predetermined positions and when said one solenoid is deenergized said spring collapses and snap moves the last mentioned armature thereagainst and transmits the kinetic energy of said armature therethrough to said member to tend to move said member from said one predetermined position, and when the other of said solenoids is energized the armature associated therewith is moved to its one position and stretches the spring attached thereto to resiliently urge said operating member to the other of said predetermined positions and when said other solenoid is deenergized the last mentioned spring collapses and snap moves the last mentioned armature thereagainst and transmits the kinetic energy of the last mentioned armature therethrough to said member to tend to move said member from said other predetermined position.

6. In a machine tool or the like having a selective drive mechanism including an operating member. shiftable to and from a predetermined position, mechanism to shift said member comprising in combination, electromagnetic means including an element movable to one position in response to energization of said means, and an extendable spring interconnecting said member and element, the length of said spring and the travel of said element being such that when said member is in said predetermined position and said means is deenergized said spring is collapsed with adjacent segments engaging one another and forming a substantially non-compressible thrust member between said element and member and when said means is energized said spring is stretched to urge said member to said predetermined position, whereby upon deenergization of said means said spring collapses and draws said element thereagainst and transmits the kinetic energy of said element therethrough to said ember to tend to shift said member from said predetermined position.

HALLIS N. STEPHAN.

REFERENCES CITED The following references are of record in the file of this patent:

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